Guide - How to wire up thermofans

[Mos]

well it turns out that i got two normally open switches instead of one no and one nc...

That would explain some of it.

this is what i had done...

That should fine, provided that part of the water pump gets hot enough, fast enough. Electrically that should be fine but I would use the crimp spade connectors on these as well.
Only proviso, and I'm sure you know it, is to use black for ground, but obviously it won't stop it from working.

wrong switch and relays are not much help, bad luck and knowledge doesn't do anyone any good. sorry for being an annoyance aswell just frustrated because i couldn't figure it out.

Unfortunately what you have hooked up is not correct. I just realised Witzl screwed up the diagram I owe you an apology - sorry I guess 4 pages of people didn't pick it up... (He didn't screw up where you said he did, but the 2nd relay red wire should go to pin 30 (bottom middle vertical) instead of 87 (top middle horizontal).

The first relay works.
The second relay has both the batt and fan connected to either two pin 87 or one 87 and one 87a depending on what kind of relay you have used. What you should have hooked up is the batt to pin 30 and the fan to pin 87a (87a is correct as long as it's an 87/87a relay).
Being pedantic, and once again won't stop it from working, is that "ign" should be a red wire by convention.

also my two original relays show that pins 87 and 87a are not connected which is why they power wasn't going to the fans...these are the three relays, i have 2 of the 1st and one of the second,

87 and 87a are never connected together, and I have never seen 86/86a in that fashion.
Below are the standard relays commonly available - all have pins 85 and 86 as the solenoid, and applying power across those pins activates the relay.
The first is a 4 pin, normally open type, with an input on pin 30 and a single ouput on pin 87.
The second is a 5 pin, normally open type, with an input on pin 30 and two outputs on two pins marked 87.
The third is a switching or "change over" 5 pin, with an input on pin 30, a normally closed output on pin 87a and a normally open output on pin 87. Sometimes the "a" is printed away from the 87 and is not immediately obvious.

I don't think either will work with the method shown by witzl. so i am going to just wire a simple NO setup now instead...

Witzl's setup is correct provided the correct relays are used.
Should be something like this:


This circuit operates as follows:



An NO setup will be fine, and is simpler than an NC setup.


This circuit operates as follows:


In your case, replacing the "ground" wire on the first relay with the wire from the thermostat should work.

HTH.
Mos.

[chaserbuddy]

i knew there might have been a mistake somewhere because normally things don't work out this hard haha, thanks for all your help Mos +rep for you

[Smokey228]

If your running two fans, does one power cable to to the first fan and then bridge to the next fan aswel? Or do you need more relays?

And mos, on the first relay in the two relay configuration, how come battery power goes to the wire that goes to the second relay? Wouldnt that mean that even when ing is off, the 2nd relay will stay powered? Or am i just wrong

Cheers,
Jase

[chaserbuddy]

If your running two fans, does one power cable to to the first fan and then bridge to the next fan aswel? Or do you need more relays?

And mos, on the first relay in the two relay configuration, how come battery power goes to the wire that goes to the second relay? Wouldnt that mean that even when ing is off, the 2nd relay will stay powered? Or am i just wrong

Cheers,
Jase

yes bridges to the other fan. i think i can help with the second question aswell when to coil is uncharged i.e ignition off, the switch switches back, stopping the battery power from going though the switch and to the next relay.

[Mos]

Personally I would not bridge a second fan off the same relays. Even though the relays are rated at 20 or 30 Amps, the spade pins are only rated around 15A, and a single relay and base will melt over time with two fans (had it happen). For peace of mind, a single fan per circuit

And yes, when you turn the ignition off, the relay solenoid is de-energised and the relay contact opens.

[VA61DETT]

Nice write up Mos!

I was almost about to draw up the cct myself, but was lazey ;p

-A

[Cuzzo]

The good thing about the whitzls diagram aswell as toyota factory, when you remove the plug from the thermo switch on the remote thermo housing (4age ae82) the thermo turns on.

[rogue-vl]

What switch range is everyone using for the 1JZ, I have a 95 on 90 off, the engine at idle runs at 96-98 so the fans never switch off, maybe i have the wrong range, maybe there is an issue with the rad .....what do you think?

[LeeRoy]

You either need a higher rated switch or a lower rated thermostat.

I'd be more inclined to get a cooler thermostat.

[Smokey228]

Personally I would not bridge a second fan off the same relays. Even though the relays are rated at 20 or 30 Amps, the spade pins are only rated around 15A, and a single relay and base will melt over time with two fans (had it happen). For peace of mind, a single fan per circuit

And yes, when you turn the ignition off, the relay solenoid is de-energised and the relay contact opens.

So in total i'll need 4 relays?? 2 for each fan??

Cheers,
Jase

[The Witzl]

Hey - i made a booboo... and it took 3 years for people to work it out!!

LOL t o y m o d s !

[Mos]

So in total i'll need 4 relays?? 2 for each fan??

If you want to wire it up like this and be sure it won't melt, yes Or use high current relays - ie with 9.5mm spade connectors.
You could chance it - I did, once, and never will again (with two fans drawing under 7A each (measured) with 30A relays). I do, however, tend to hook them up with NO thermostats to reduce the number of relays.
Toyota uses 30A circuits and 8.5mm connectors for fans and they would have done sufficient R&D to determine that this was the most optimal solution.

Hey - i made a booboo... and it took 3 years for people to work it out!!
LOL t o y m o d s !

So is that saying that no one has used the information It "looked" right, I just never had a good look for the pin number on the relays

Mos.

[Cuzzo]

Hey - i made a booboo... and it took 3 years for people to work it out!!

LOL t o y m o d s !

can someone explain the failz to me. ive used the diagram straight up and it works fine.

[Mos]

It required the relay to make a connection between 87 and 87A which means it will do nothing. If you substitute a relay with two 87pins, then it just shorts and runs the fan full time.

[SillyCarS]

ok so im wiring my microtech to twin thermos in a 23 celica. just posting here so folks can see how im doing it with the single output from the comp

i bought 2 supercheap 12" thermos. the brand is calibre and they go for about $60 each.



the relays that are supplied are 40A so im happy to just run the signal from the microtech in parrallel to each relay for switching (for the n00bs this means the power remains the same for the signal wrather than being split in two when you wire in series, which will halve the 6v power (which is what i think microtech runs at) output to 3v which is hardly sufficient (i think)) the other black box jigga that you can is a 15A fuse, which is also supplied



the fans are to be mounted on a hyundai excel radiator which looks like this



so mounting the fans is the biggest pain in the arse you're gunna have to deal with. first off you get given a whole bunch of shit, nfi how your supposed to use it. and ofcourse the fins will never line up the way you would like them to



or you could just line it up and drill through the fan housing itself. much easier.



then put you bolts in and gently tap them. this will show you where to pry apart the radiator fins for you bolts. i drilled mine. i found it doesn't acutally remove any material, it separates in nicely though





finished



EDIT: this will be edited as i go